Telecommunications method and apparatus for facilitating positioning measurements

ABSTRACT

A wireless terminal ( 30 ) capable of operating in a discontinuous mode and method for operation facilitate measurements pertaining to position of the wireless terminal ( 30 ). A measurement request message from a radio access network ( 28 ) indicates that measurements are to be performed by the wireless terminal on downlink signals transmitted by the base station or by the base station on downlink signals transmitted by the base station. As a result of or after receiving the message, operation of the wireless terminal ( 30 ) changes from a discontinuous mode to a modified mode to facilitate performance of the measurements. Relative to the discontinuous mode at least one of following are shortened or eliminated in the modified mode: (i) the non-reception periods, and (ii) the non-transmission periods.

This application is a continuation application of U.S. patentapplication Ser. No. 12/488,303, filed Jun. 19, 2009, the entirecontents of which is hereby incorporated herein.

TECHNICAL FIELD

This invention pertains to telecommunications, and particularly tomethod and apparatus for performing measurements, particularly when awireless terminal is or has been operating in a discontinuous reception(DRX) and/or a discontinuous transmission (DTX) mode.

BACKGROUND

In a typical cellular radio system, wireless terminals (also known asmobile stations and/or user equipment units (UEs)) communicate via aradio access network (RAN) to one or more core networks. The wirelessterminals can be mobile stations or user equipment units (UE) such asmobile telephones (“cellular” telephones) and laptops with wirelesscapability, e.g., mobile termination, and thus can be, for example,portable, pocket, hand-held, computer-included, or car-mounted mobiledevices which communicate voice and/or data with radio access network.

The radio access network (RAN) covers a geographical area which isdivided into cell areas, with each cell area being served by a basestation, e.g., a radio base station (RBS), which in some networks isalso called “NodeB”, “B node”, or (in LTE) eNodeB. A cell is ageographical area where radio coverage is provided by the radio basestation equipment at a base station site. Each cell is identified by anidentity within the local radio area, which is broadcast in the cell.The base stations communicate over the air interface operating on radiofrequencies with the user equipment units (UE) within range of the basestations.

In some versions of radio access networks, several base stations aretypically connected (e.g., by landlines or microwave) to a radio networkcontroller (RNC). The radio network controller, also sometimes termed abase station controller (BSC), supervises and coordinates variousactivities of the plural base stations connected thereto. The radionetwork controllers are typically connected to one or more corenetworks.

The Universal Mobile Telecommunications System (UMTS) is a thirdgeneration mobile communication system, which evolved from the GlobalSystem for Mobile Communications (GSM), and is intended to provideimproved mobile communication services based on Wideband Code DivisionMultiple Access (WCDMA) access technology. UTRAN is essentially a radioaccess network using wideband code division multiple access for userequipment units (UEs). An entity known as the Third GenerationPartnership Project (3GPP) has undertaken to evolve further the UTRANand GSM based radio access network technologies.

Specifications for the Evolved Universal Terrestrial Radio AccessNetwork (E-UTRAN) are ongoing within the 3rd Generation PartnershipProject (3GPP). Another name used for E-UTRAN is the Long Term Evolution(LTE) Radio Access Network (RAN). Long Term Evolution (LTE) is a variantof a 3GPP radio access technology wherein the radio base station nodesare connected directly to a core network rather than to radio networkcontroller (RNC) nodes. In general, in LTE the functions of a radionetwork controller (RNC) node are performed by the radio base stationsnodes. As such, the radio access network (RAN) of an LTE system has anessentially “flat” architecture comprising radio base station nodeswithout reporting to radio network controller (RNC) nodes. The evolvedUTRAN (E-UTRAN) comprises evolved base station nodes, e.g., evolvedNodeBs or eNBs, providing evolved UTRA user-plane and control-planeprotocol terminations toward the wireless terminal.

In LTE as in other radio access technologies, it is advantageous for thenetwork to know with reasonable accuracy the geographical position of awireless terminal (UE). In fact, some countries or jurisdictions mandatethat the network be able to locate the UE within a prescribed distancerange (e.g., a few tens of meters) and within a stipulated timeduration. This requirement is often imposed for facilitating services toUE, such as emergency services to a person operating the UE, or forsecurity management reasons.

Knowledge of the UE's geographical whereabouts typically comes from theUE determining its own geographical position and reporting thatgeographical position to the network, as well as to the person operatingthe UE. This capability for the person operating the UE to know his/herlocation can be of considerable value to the UE operator, and indeedsubscriptions to such location-reporting service can be a source ofrevenue for a network operator.

The Global Navigation Satellite System (GNSS) is the standard genericterm for satellite navigation systems that enable subscribers such as UEoperators to locate their position and to acquire other relevantnavigational information. The global positioning system (GPS) and theEuropean Galileo positioning system are well known examples of GNSS.

Not only Global Navigation Satellite System (GNSS) but also non-GNSSpositioning methods have been employed for determining UE position.According to one proposal, in some contexts a GNSS based-positioningmethod may be employed as a primary positioning technique, while anon-GNSS positioning method may be employed as a secondary or backuppositioning technique. See, in this regard, RP-080995, Work Item,“Positioning Support for LTE”, Qualcomm (Rapporteur), which isincorporated herein by reference. Other UE positioning techniques aredescribed, e.g., in the following: (1) RP-070926, Study Item,“Evaluation of the inclusion of Pattern Matching Technology in theUTRAN”, Polaris Wireless (Rapporteur); and (2) RP-090354, Work Item,“Networ12-Based Positioning Support for LTE”, True Position(Rapporteur), both of which are incorporated herein by reference intheir entirety.

The non-GNSS positioning methods are often also referred to asterrestrial positioning methods. These terrestrial positioning methodsusually determine UE position on the basis of signals measured by the UEand/or radio network nodes such as base station. Examples of suchsignals and methods include cell identity based methods; network-basedmethods which detect the uplink time difference of arrival (U-TDOA) ofsignals at different base stations; UE-based methods which observe thetime difference of arrival (OTDOA) of signals from three or more cells;and fingerprinting or pattern matching positioning methods.

Some of these terrestrial positioning methods such as cell ID based andpattern matching positioning technology make use of normal UE neighborcell measurements such as the detected cell identity, received signalstrength, path loss etc. On the other hand, certain methods such asU-TDOA and OTDOA require specific measurements. Some of the measurementssuch as time difference of arrival can also be reused for other purposessuch as time alignment at handover, support for cell synchronization,etc.

In the 3rd Generation Partnership Project (3GPP), a layer 3 protocolknown as the Radio Resource Control (RRC) layer defines various RRCstates to describe the usage of radio resources for the UE. There is adifference in the number of states in UTRAN on the one hand, and LTE onthe other hand.

The 3rd Generation Partnership Project (3GPP) also supports a featureknown as discontinuous reception (DRX). Discontinuous reception (DRX)enables a UE to save power by turning off some or all of its radiocircuitry when not needed, thereby increasing battery lifetime of theUE. Discontinuous reception (DRX) is described and utilized in anotherperspective in U.S. patent application Ser. No. 12/475,953, filed Jun.1, 2009, entitled “USING MOBILITY STATISTICS TO ENHANCETELECOMMUNICATIONS HANDOVER”, which is incorporated herein by referencein its entirety.

In UTRAN there are several RRC states: Idle state; CELL_PCH state;URA_PCH state; CELL_FACH state; and CELL_DCH state. In E-UTRAN in idlestate the UE is known on a tracking area level, which comprises ofmultiple set of cells (e.g. 100-300 cells). Similarly in the CELL_DCHstate the UE uses dedicated radio resources that are not shared withother UEs; the UE is known on a cell level according to its currentactive set; and, the UE can use dedicated transport channels, downlinkand uplink shared transport channels, or a combination of transportchannels. In the UTRAN CELL_FACH state no dedicated physical channel isassigned to the UE; the UE continuously monitors a FACH channel in thedownlink; and, the UE is assigned a default common or shared transportchannel in the uplink (e.g., RACH). In the UTRAN CELL_PCH or URA_PCHstate no dedicated physical channels is assigned to the UE; no uplinkactivity is possible; and, the UE receives paging or broadcastinginformation from the UTRAN. Discontinuous reception (DRX) is now used inall these UTRAN RCC states according to 3GPP release 7 and beyond. Butfor the CELL_FACH and CEL_DCH states the allowed DRX cycles are muchshorter. Specifically, for CELL_DCH max DRX cycle=40 ms.

For LTE there are only two RRC states: Idle state and Connected state.DRX is used in both LTE states, with the DRX cycles in both statesranging from 10 ms to 2.56 sec.

Although the ensuing discussion and description focus on discontinuousreception (DRX) operation in LTE, it should be understand that thediscussion and descriptions are not limited to LTE but can apply toother environments including UTRAN.

A DRX “cycle” comprises an “on duration” and a “DRX period”. During the“on duration” portion of the cycle the user equipment unit (UE) shouldmonitor a channel known as the Dedicated Physical Control CHannel(PDCCH) for scheduling assignments in RRC connected state. In LTE thepaging is also mapped on PDCCH. Therefore UE in idle state also monitorsPDCCH for the reception of paging. During the “DRX period” the UE canskip reception of downlink channels for battery saving purposes. ThusDRX has a tradeoff between battery saving and latency: on the one hand,a long DRX period is beneficial for lengthening the battery life of theUE; on the other hand, a shorter DRX period is better for fasterresponse when data transfer is resumed.

In general the DRX function is configured and controlled by the network.The UE behavior is based on a set of rules that define when the UE mustmonitor the Dedicated Physical Control CHannel (PDCCH) for schedulingassignments.

When the UE does not have an established radio-resource control (RRC)connection, i.e., when no radio bearers are configured for radiotransmission involving the UE, the UE is generally “asleep” abut wakesup and monitors the paging every DRX cycle.

On the other hand, when the UE has an RRC connection and the DRXfunction is operative (e.g., RRC connected state in LTE), the DRXfunction is characterized by the aforementioned DRX cycle, theaforementioned on-duration period, and an inactivity timer. The UE wakesup and monitors the PDCCH at the beginning of every DRX cycle for theentire on duration period. When a scheduling message is received duringan “on duration”, the UE starts the inactivity timer and monitors thePDCCH in every subframe while the inactivity timer is running. Duringthis period, the UE can be regarded as being in a reception mode.Whenever a scheduling message is received while the inactivity timer isrunning, the UE restarts the inactivity timer. When the inactivity timerexpires the UE moves back into another DRX cycle. If no schedulingassignment is received, the UE falls asleep again.

Thus, in E-UTRAN or LTE the DRX feature is used in both idle and RRCconnected modes. The aforementioned positioning measurements aretypically done in connected mode. Furthermore in E-UTRAN, there can be awide range of DRX cycles (e.g., cycle lengths) for use in the RRCconnected mode as allowed by the network. For example, the DRX (i.e.,the time length of the DRX cycle) can vary between 10 ms to 2.56seconds. With the increase in the DRX cycle, there is more time betweenmeasurements, and thus the measurement performance of measurementquantities can deteriorate since the UE may only sparsely (e.g., lessfrequently) measure on signals received from the cells. When the UE isin the DRX state the measurement period can also be set to be longer andthe length of the measurement period can vary with the DRX cycle.

Measurement period is a concept well known in telecommunications, e.g.UTRAN and E-UTRAN. As illustrated in FIG. 16, one measurement periodrequires comprises several samples (e.g. 4-5 samples) from each of thecells being samples. The number of samples can vary, e.g., can beimplementation-specific. FIG. 16 illustrates a situation in which thereare (by way of example) four cells whose signals are measured, and foursamplings of each cell. In a non-DRX mode the measurement period isstandardized to be 200 milliseconds. The samplings for the cells can beaveraged over the measurement period.

Typically the measurement period of a measurement quantity is K timesthe DRX cycle, e.g. 5 times the DRX. As an example for DRX cycle of 2.56seconds the measurement period of reference signal received power(RSRP), which is LTE measurement quantity, is approximately 10.28seconds. During a single measurement period the wireless terminal (UE)is also capable of performing a particular type of measurement (such asRSRP) from certain number of cells, e.g. 6 or 8 cells including theserving cell. The measurement periods of all standardized measurementquantities for the continuous reception (non DRX case) and for allallowed DRX cycles are pre-defined in the 3GPP standard. Similarly thenumber of cells from which the UE is required to perform certainmeasurement quantity over the measurement period is also specified inthe standard.

So if the measurement period of the positioning measurement is alsoextended due to DRX, then the measurement reporting delay will increase,and thus the response time in determining the wireless terminal (UE)positioning will be longer. These phenomena can negatively impactaccuracy of a determination of wireless terminal (UE) position.

The accuracy of UE positioning determination can not only be affected bydiscontinuous reception (DRX), but by discontinuous transmission (DTX)as well. That is, discontinuous transmission (DTX) such as discontinuouspower control and use of idle gaps for measurements, can also affect thepositioning performance. Discontinuous transmission (DTX) ischaracterized by periodic pattern of activity or transmission followedby relatively longer inactivity or idle periods.

In case of uplink discontinuous transmission (DTX) the base station willless frequently (e.g., sparsely) receive signals from the UE, and hencewould have less opportunity for performing measurements. A longerdiscontinuous transmission (DTX) will lead to longer measurement periodand thus longer response time in determining the UE position. Forinstance, a round trip time (RTT) measurement done at the base stationfor network based positioning will be delayed when discontinuoustransmission (DTX) is used.

In UTRAN, discontinuous transmission (DTX) is characterized bydiscontinuous power control channel (DPCCH) and is used to reduce theinterference and UE power. Similarly other idle gaps such as compressedmode gaps and measurement gaps are used in UTRAN and E-UTRANrespectively.

Positioning measurements are typically performed in RRC connected state.In legacy systems such as UTRAN FDD and TDD, some positioning specificmeasurements and corresponding procedures exist. In these legacy systemsthe longest allowed discontinuous reception (DRX) cycle in RRC connectedstate is limited to 40 ms, and the measurement period of all UEmeasurements (including positioning measurements) scales with the DRXcycle. For instance, the WCDMA SFN-SFN type 2 positioning relatedmeasurement is performed, when UE receiver is active, simultaneously todata reception. This means, depending upon the DRX cycle, themeasurement period in DRX is longer than in the non DRX case. Howeverdue to shorter DRX (40 ms) in UTRAN CELL_DCH, the impact of the DRX onthe positioning performance is not very significant.

In E-UTRAN the DRX cycle in RRC connected state can range up to 2.56seconds. In DRX state traditionally the measurement period of ameasurement quantity is K times DRX cycle, e.g. 10.28 seconds for 2.56seconds DRX cycle assuming scaling factor of 5. This level ofmeasurement period is very long for the positioning measurement.Therefore scaling of the measurement period when discontinuous reception(DRX) in E-UTRAN is used is not desirable. This is because the extendedmeasurement period will adversely affect the positioning accuracy (i.e.response from UE) and might prevent achieving the positioning accuracyrequirements.

The discontinuous transmission (DTX) may also impact the accuracy andresponse time of positioning performance. Especially uplink measurementssuch as round trip time (RTT) can be delayed if the UE is operatingunder longer DTX level or cycle.

SUMMARY

In one of its diverse aspects the technology disclosed herein concerns amethod of operating a wireless terminal in communication with a radioaccess network over a radio interface. The wireless terminal is of atype capable of operating in a discontinuous mode comprising at leastone of non-reception periods between reception periods andnon-transmission periods between transmission periods. The methodcomprises receiving a message from the radio access network thatindicates that measurements are to be performed by the wireless terminalon downlink signals transmitted by one or more nodes of the radio accessnetwork (e.g., on downlink signals transmitted by the base station) orby the radio access network on uplink signals transmitted by thewireless terminal. The method further comprises, as a result of or afterreceiving the message, changing operation of the wireless terminal froma discontinuous mode to a modified mode to facilitate performance of themeasurements. Relative to the discontinuous mode at least one offollowing are shortened or eliminated in the modified mode: (i) thenon-reception periods, and (ii) the non-transmission periods.

In some example embodiments, the measurements are performed by thewireless terminal and the message is a measurement request message whichis configured to direct the wireless terminal to perform measurementsrelative to signals received by the wireless terminal from one or morecells of the radio access network. In other example embodiments themessage is transmitted when the radio access network is to perform themeasurements and the wireless terminal needs to be in the modified modeduring performance of the measurements.

As explained and utilized herein, “changing from a discontinuous mode .. . to a modified mode” comprises one or more of: (1) changing mode ofthe wireless terminal (e.g., changing from a discontinuous mode [such asdiscontinuous reception (DRX) or discontinuous transmission (DTX)] to acontinuous transmission mode); (2) changing from the discontinuous mode(a first discontinuous mode) to a modified discontinuous mode (a seconddiscontinuous mode). The changing from the (first) discontinuous mode toa modified (second) discontinuous mode can involve changing a parameteror value associated with the discontinuous mode, e.g., changing (e.g.,shortening) a parameter or value such as a discontinuous reception (DRX)cycle value or a discontinuous transmission (DTX) level value.

In an example embodiment the discontinuous mode is a discontinuousreception (DRX) mode. In another example embodiment the discontinuousmode is a discontinuous transmission (DTX) mode. In yet another exampleembodiment the discontinuous mode includes both discontinuous reception(DRX) mode and discontinuous transmission (DTX).

In an example embodiment the modified mode is a continuous mode. Inanother example embodiment the modified mode comprises a modifieddiscontinuous mode having a modified discontinuous mode parameter, themodified discontinuous mode parameter being indicative of a shortercycle than a previous discontinuous mode parameter. In this latterembodiment, the act of changing, as a result of receiving the message,can comprise changing from a first discontinuous mode characterized by afirst discontinuous mode value to a second discontinuous modecharacterized by a second discontinuous mode value; and, upon completionof the performance of the measurements; reverting back to the firstdiscontinuous mode. In an example embodiment, the second discontinuousmode value is smaller or shorter than the first discontinuous modevalue. In an example implementation, the discontinuous mode is adiscontinuous reception (DRX) mode and the first discontinuous modevalue and the second discontinuous mode value are differingdiscontinuous reception (DRX) cycle lengths. In another exampleimplementation, the discontinuous mode is a discontinuous transmission(DTX) mode and the first discontinuous mode value and the seconddiscontinuous mode value are differing discontinuous transmission (DTX)level values.

In an example embodiment the measurements are for determining positionof the wireless terminal. In an example implementation, the message is ameasurement request message which is configured to direct the wirelessterminal to measure time difference of arrival of the signals receivedby the wireless terminal from plural cells of the radio access network.In another example implementation the measurement request message isconfigured to direct the wireless terminal to measure reference signaltime difference (RSTD) of signals received by the wireless terminal fromplural cells of the radio access network. The RSTD measurement can beperformed by the wireless terminal on any suitable reference or pilot orany known signals received from plural cells. For instance the referencesignals may be common reference signals, which are also used for othermeasurements, or positioning reference signals, which are primarilytransmitted to facilitate positioning measurement.

In an example embodiment, the method further comprises changing from thediscontinuous mode in accordance with a mode change timing factor (MCTF)which influences when a mode change occurs from the discontinuous modeto the modified mode. In an example implementation the method furthercomprises pre-configuring the mode change timing factor (MCTF) at thewireless terminal prior to reception of the message. In another exampleimplementation the method further comprises including the mode changetiming factor (MCTF) in the message.

In an example embodiment the method further comprises, upon completionof the performance of the measurements, reverting back to thediscontinuous mode from the modified mode after expiration of apost-measurement mode revert timing factor (MRTF) which influencestiming of a reversion from the modified mode to the discontinuous mode.

In an example embodiment, changing from the discontinuous mode to themodified mode comprises disabling one or both of discontinuous reception(DRX) and discontinuous transmission (DTX).

In another of its aspects the technology disclosed herein concernsanother method of operating a wireless terminal in communication with aradio access network over a radio interface. The method comprisesreceiving a message from the radio access network that indicates thatmeasurements are to be performed by the wireless terminal on downlinksignals transmitted by one or more nodes of the radio access network(e.g., on downlink signals transmitted by the base station) or by theradio access network on uplink signals transmitted by the wirelessterminal; and, as a result of receiving the message, ignoring ormodifying the discontinuous mode while the wireless terminal performsthe measurements. In some example embodiments the message is ameasurement request message which is configured to direct the wirelessterminal to perform measurements on signals received by the wirelessterminal from one or more cells of the radio access network.

In another of its aspects the technology disclosed herein concernsanother method of operating a wireless terminal in communication with aradio access network over a radio interface. The method comprisesreceiving a message from the radio access network that indicates thatmeasurements are to be performed by the wireless terminal on downlinksignals transmitted by the base station or by the radio access networkon uplink signals transmitted by the wireless terminal; and, as a resultof receiving the message; providing a shorter or moderate measurementperiod for the wireless terminal to perform the measurementscorresponding to that of a shorter or a moderate DRX cycle. In someexample embodiments the message is a measurement request message whichis configured to direct the wireless terminal to perform measurements onsignals received by the wireless terminal from one or more cells of theradio access network.

In another of its aspects the technology disclosed herein concerns awireless terminal configured for communication with a radio accessnetwork over a radio interface. The wireless terminal is of a typecapable of operating in a discontinuous mode comprising at least one ofnon-reception periods between reception periods and non-transmissionperiods between transmission periods. The wireless terminal comprises atransceiver and a computer-implemented radio resource control (RRC)unit. The transceiver is configured to receive a message from the radioaccess network that indicates that measurements are to be performed bythe wireless terminal on downlink signals transmitted by the basestation or by the radio access network on uplink signals transmitted bythe wireless terminal. The radio resource control (RRC) unit isconfigured, as a result of receiving the message, to change the wirelessterminal from the discontinuous mode to a modified mode to facilitateperformance of the measurements. The discontinuous mode is configured tocomprise at least one of non-reception periods between reception periodsand non-transmission periods between transmission periods. Relative tothe discontinuous mode the modified mode is configured to shortened oreliminated at least one of following: (i) the non-reception periods, and(ii) the non-transmission periods. In some example embodiments themessage is a measurement request message which is configured to directthe wireless terminal to perform measurements relative to the positiondetermination signals, and the transceiver is configured to receivedposition determination signals from one or more cells of the radioaccess network.

In an example embodiment the discontinuous mode is a discontinuousreception (DRX) mode. In another example embodiment the discontinuousmode is a discontinuous transmission (DTX) mode.

In an example embodiment the modified mode is a continuous mode. Inanother example embodiment the modified mode comprises a modifieddiscontinuous mode having a modified parameter, the modified parameterbeing shorter than a previous parameter.

In an example embodiment the radio resource control (RRC) unit isfurther configured, as a result of receiving the message, to change theoperation of the wireless terminal from a first discontinuous modecharacterized by a first discontinuous mode value to a seconddiscontinuous mode characterized by a second discontinuous mode value;and, upon completion of the performance of the measurements, to revertback to the first discontinuous mode. In an example implementation, thesecond discontinuous mode value is smaller or shorter than the firstdiscontinuous mode value. In an example implementation, thediscontinuous mode is a discontinuous reception (DRX) mode and the firstdiscontinuous mode value and the second discontinuous mode value arediffering discontinuous reception (DRX) cycle lengths. In anotherexample implementation, the discontinuous mode is a discontinuoustransmission (DTX) mode and the first discontinuous mode value and thesecond discontinuous mode value are differing discontinuous transmission(DTX) level values.

In an example embodiment the wireless terminal further comprises ameasurement unit configured to perform the measurements for determiningposition of the wireless terminal. In an example implementation themeasurement request message is configured to direct the measurement unitof the wireless terminal to measure time difference of arrival of thesignals received by the wireless terminal from plural cells of the radioaccess network. In another example implementation the measurementrequest message is configured to direct the measurement unit of thewireless terminal to measure reference signal time difference (RSTD) ofsignals received by the wireless terminal from plural cells of the radioaccess network.

In an example embodiment the radio resource control (RRC) unit isconfigured to change from the discontinuous mode in accordance with amode change timing factor (MCTF) which influences when a mode changeoccurs from the discontinuous mode to the modified mode. In an exampleimplementation the mode change timing factor (MCTF) is pre-configured atthe wireless terminal prior to reception of the message. In anotherexample implementation the mode change timing factor (MCTF) is includedin the message.

In an example embodiment the radio resource control (RRC) unit isfurther configured, upon completion of the performance of themeasurements, to revert back to the discontinuous mode from the modifiedmode after expiration of a post-measurement mode revert timing factor(MRTF) which influences timing of a reversion from the modified mode tothe discontinuous mode.

In an example embodiment the radio resource control (RRC) unit isconfigured to change from the discontinuous mode to the modified mode bydisabling one or both of discontinuous reception (DRX) and discontinuoustransmission (DTX).

In another of its aspects the technology disclosed herein concerns awireless terminal configured to operate in communication with a radioaccess network over a radio interface. The wireless terminal comprises atransceiver and a computer-implemented radio resource control (RRC)unit. The transceiver is configured to receive a message from the radioaccess network that indicates that measurements are to be performed bythe wireless terminal on downlink signals transmitted by the basestation or the radio access network on uplink signals transmitted by thewireless terminal. The radio resource control (RRC) unit of the wirelessterminal is configured, as a result of receiving the message, to ignoreor modify the discontinuous mode while the wireless terminal while thewireless terminal performs the measurements. In an example embodiment,the message is a measurement request message which is configured todirect the wireless terminal to perform measurements for the positiondetermination signals on signals transmitted from plural cells of theradio access network, and the transceiver is further configured toreceive position determination signals from one or more cells of theradio access network.

In another of its aspects the technology disclosed herein concerns anode of a radio access network (RAN) which is configured for operationover a radio interface with a wireless terminal. The node comprises acomputer-implemented node radio resource control (RRC) unit and atransceiver. The radio resource control (RRC) unit is configured toprepare a measurement request message for transmission to the wirelessterminal. The measurement request message is configured both to directthe wireless terminal to perform measurements for the positiondetermination on signals transmitted from plural cells of the radioaccess network and to provide the wireless terminal with a parameter tobe used by the wireless terminal for facilitating performance of themeasurements by the wireless terminal by changing operation of thewireless terminal from a discontinuous mode to a modified mode. Thediscontinuous mode is configured to comprise at least one ofnon-reception periods between reception periods and non-transmissionperiods between transmission periods. Relative to the discontinuous modethe modified mode is configured to shortened or eliminated at least oneof following: (i) the non-reception periods, and (ii) thenon-transmission periods. The transceiver is configured to transmit themeasurement request message to the wireless terminal over the radiointerface.

In an example embodiment the discontinuous parameter is for adiscontinuous reception (DRX) mode. In another example embodiment thediscontinuous parameter is for a discontinuous transmission (DTX) mode.In yet another example embodiment the discontinuous parameterencompasses one or more of the discontinuous reception (DRX) mode thediscontinuous transmission (DTX) mode.

In an example embodiment the measurements are for determining positionof the wireless terminal.

In an example embodiment the measurement request message is configuredto direct the wireless terminal to measure time difference of arrival ofthe signals received by the wireless terminal from plural cells of theradio access network. In another example embodiment the measurementrequest message is configured to direct the wireless terminal to measurereference signal time difference (RSTD) of signals received by thewireless terminal from plural cells of the radio access network.

In an example embodiment the discontinuous parameter comprises apre-change time offset. In another example embodiment the discontinuousparameter comprises a post-measurement mode revert timing factor (MRTF)which influences timing of a reversion from the modified mode to thediscontinuous mode.

Thus the technology disclosed herein encompasses defining a rule or setof rules need to facilitate positioning measurements when wirelessterminal (UE) is in DTX/DRX modes. Such rules ensure good positioningperformance to guarantee that various regulatory requirements andemergency call service targets are met.

Therefore, suitable procedures and methods and apparatus are providedfor performing positioning related measurements such as observed timedifference of arrival in DRX state. The technology disclosed hereindiscloses method and arrangement for the time difference of signalsarrival type of measurements for determining UE positioning in DRXstate. The technology disclosed herein also discloses methods forperforming positioning measurements in DTX mode. The technologydisclosed herein is applicable to other positioning measurementsperformed by wireless terminal (UE) or by the network node in DRX and/orDTX states. The technology disclosed herein is also applicable for anymeasurement performed by the wireless terminal (UE) or by the networknode in DRX and/or DTX states.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments as illustrated in the accompanyingdrawings in which reference characters refer to the same partsthroughout the various views. The drawings are not necessarily to scale,emphasis instead being placed upon illustrating the principles of theinvention.

FIG. 1 is schematic diagram of a portion of a radio access networkincluding a representative network node and a representative wirelessterminal.

FIG. 2 is a topographical view of an example cell arrangement for acommunications network.

FIG. 3 is a flowchart showing basic, example acts or steps comprising anexample embodiment of a method of operating a wireless terminal.

FIG. 4 is a flowchart showing basic, example acts or steps comprising anexample embodiment of a method of operating a wireless terminal whichincludes an act of the wireless terminal reverting back from themodified mode to the discontinuous mode upon completion of theperformance of the measurements.

FIG. 5 is a diagrammatic view generically illustrating the concept ofchanging from a discontinuous mode to a modified mode. FIG. 5A-FIG. 5Care diagrammatic views showing example specific situation of changingfrom a discontinuous mode to a modified mode.

FIG. 6 is schematic diagram of a portion of representative wirelessterminal according to an example embodiment.

FIG. 7 is schematic diagram of a portion of a radio access networkincluding a representative network node and a representative wirelessterminal wherein a mode change from a discontinuous mode to a modifiedmode occurs in accordance with a mode change timing factor.

FIG. 8 is a diagrammatic view illustrating a timing sequence of thenetwork of FIG. 7.

FIG. 9 is schematic diagram of a portion of a radio access networkincluding a representative network node and a representative wirelessterminal wherein, upon completion of the performance of themeasurements, the wireless terminal reverts back to a discontinuous modefrom a modified mode in accordance with a post-measurement mode reverttiming factor.

FIG. 10 is a diagrammatic view illustrating a timing sequence of thenetwork of FIG. 9.

FIG. 11 is a flowcharting showing example acts or steps included in anon-limiting example method of a mode change operation which involveschanging from a discontinuous mode to a continuous mode.

FIG. 12 is a flowcharting showing example acts or steps included in anon-limiting example method of a mode change operation which involveschanging from a first discontinuous mode to a second discontinuous modehaving a shortened cycle length.

FIG. 13 is a schematic diagram of a portion of an example embodiment ofa radio access network including a representative network node and arepresentative wireless terminal wherein the network node directs thewireless terminal to discontinue the discontinuous transmission (DTX)mode while the network node makes position measurements for the wirelessterminal.

FIG. 14 is a flowcharting showing example acts or steps included in anon-limiting example method of a mode change operation for theembodiment of FIG. 13.

FIG. 15 is a diagrammatic view which contrasts an example measurementperiod of a discontinuous mode situation and an example measurementperiod of a non-discontinuous mode situation resulting from a modechange.

FIG. 16 is a diagrammatic view showing an example measurement period.

FIG. 17 is a flowchart showing basic, example acts or steps comprisinganother example embodiment of a method of operating a wireless terminalencountering an emergency situation.

FIG. 18 is a flowchart showing basic, example acts or steps comprisingan example embodiment of a method of operating a wireless terminal whichincludes an act of the wireless terminal reverting back from themodified mode to the discontinuous mode upon cessation of an emergencysituation.

DETAILED DESCRIPTION

In the following description, for purposes of explanation and notlimitation, specific details are set forth such as particulararchitectures, interfaces, techniques, etc. in order to provide athorough understanding of the present invention. However, it will beapparent to those skilled in the art that the present invention may bepracticed in other embodiments that depart from these specific details.That is, those skilled in the art will be able to devise variousarrangements which, although not explicitly described or shown herein,embody the principles of the invention and are included within itsspirit and scope. In some instances, detailed descriptions of well-knowndevices, circuits, and methods are omitted so as not to obscure thedescription of the present invention with unnecessary detail. Allstatements herein reciting principles, aspects, and embodiments of theinvention, as well as specific examples thereof, are intended toencompass both structural and functional equivalents thereof.Additionally, it is intended that such equivalents include bothcurrently known equivalents as well as equivalents developed in thefuture, i.e., any elements developed that perform the same function,regardless of structure.

Thus, for example, it will be appreciated by those skilled in the artthat block diagrams herein can represent conceptual views ofillustrative circuitry embodying the principles of the technology.Similarly, it will be appreciated that any flow charts, state transitiondiagrams, pseudocode, and the like represent various processes which maybe substantially represented in computer readable medium and so executedby a computer or processor, whether or not such computer or processor isexplicitly shown.

The functions of the various elements including functional blockslabeled or described as “computer”, “processor” or “controller” may beprovided through the use of dedicated hardware as well as hardwarecapable of executing software in the form of coded instructions storedon computer readable medium. A computer is generally understood tocomprise one or more processors and/or controllers, and the termscomputer and processor may be employed interchangeably herein. Whenprovided by a computer or processor, the functions may be provided by asingle dedicated computer or processor, by a single shared computer orprocessor, or by a plurality of individual computers or processors, someof which may be shared or distributed. Such functions are to beunderstood as being computer-implemented and thus machine-implemented.Moreover, use of the term “processor” or “controller” shall also beconstrued to refer to other hardware capable of performing suchfunctions and/or executing software, and may include, withoutlimitation, digital signal processor (DSP) hardware, reduced instructionset processor, hardware (e.g., digital or analog) circuitry, and (whereappropriate) state machines capable of performing such functions.

FIG. 1 shows an example communications network 20 such as a radio accessnetwork (RAN). The network 20 comprises, among other possible entities,network node 22 which communicates with wireless terminal 30. In someexample implementations network node 22 takes the form of a radionetwork controller node (RNC). In other example embodiments such as LTEimplementations the network node 22 can instead take the form of a radiobase station or eNodeB.

The wireless terminal 30 can be a mobile station or user equipment unit(UE) such as a mobile telephone (“cellular” telephone) and or a laptopwith wireless capability, e.g., mobile termination, and thus can be, forexample, portable, pocket, hand-held, computer-included, or car-mountedmobile devices which communicate voice and/or data with radio accessnetwork. In various drawings the wireless terminal 30 is illustrated asor referred to as a “UE”. The wireless terminal 30 communicates over aradio or air interface 32 with communications network 20. Typically thenetwork node 22 is in communication with many wireless terminals, butfor sake of simplicity only one such wireless terminal 30 is shown.

FIG. 2 depicts in topographical format portions of a cellulararrangement of communications network 20, showing specifically examplecells C1-C6. A base station node is associated with each cell. FIG. 2further shows a representative wireless terminal 30 being located withincell C5 of communications network 20. In view, e.g., of its CDMAcapabilities and handover capabilities, the wireless terminal 30monitors (e.g., measures) signals associated with each cell, e.g., pilotsignals which include an identification of the cell from which they aretransmitted.

FIG. 1 shows wireless terminal 30 as comprising, in its most basic form,transceiver 34 and processor or computer 40. The transceiver 34 servesto facilitate one or both of downlink transmissions from communicationsnetwork 20 to wireless terminal 30 and uplink transmissions fromwireless terminal 30 to communications network 20. The transceiver 34generally comprises antenna(s), amplifiers, and associated hardwareelements for transmitting and receiving radio signals over radiointerface 32.

The computer 40 serves many purposes, including execution ofinstructions for enabling operation of wireless terminal 30 inconjunction with its own operation as well as transmission of signalsand data over radio interface 32. For illustrating the basic aspect ofthe technology disclosed herein FIG. 1 shows computer 40 as comprisingradio resource control (RRC) unit 42, which in turn comprisesmeasurement unit 44. It should be appreciated that, in other exampleembodiments, the measurement unit 44 can be located or providedexternally to radio resource control (RRC) unit 42. As explained herein,measurement unit 42 serves to perform measurements relative to pluralcells of network 20 (see FIG. 2).

The wireless terminals described herein are of a type capable ofoperating in a discontinuous mode. As used herein “discontinuous mode”comprises or encompasses at least one of non-reception periods betweenreception periods and non-transmission periods between transmissionperiods. A discontinuous mode comprising non-reception periods betweenreception periods is also known as a discontinuous reception (DRX). Adiscontinuous mode comprising non-transmission periods betweentransmission periods is also known as a discontinuous transmission(DTX).

FIG. 1 illustrates a non-limiting implementation of network node 28 in aLTE environment in which network node 28 is an eNodeB (e.g., basestation node). FIG. 1 further shows network node 28 as comprising nodetransceiver 48 and node processor or node computer 50. The nodetransceiver 48 typically comprises plural antenna along with associatedelectronics such as amplifiers, for example. The node computer 50comprises node radio resource control (RRC) unit 52.

As used herein, “transceiver” should be understood to encompass, atleast in some embodiments, plural transceivers. Moreover, the fact thata transceiver of either the wireless terminal 30 or the network node 28can be involved in a discontinuous reception (DRX) mode of operation onthe downlink does not necessarily mean that the transceiver is alsoinvolved in a discontinuous transmission (DTX) mode of operation on theuplink, or vice versa.

One of the aspects of the technology disclosed herein concerns a methodof operating a wireless terminal such as wireless terminal FIG. 3 showsexample representative acts or steps involved in a method according to afirst aspect of the technology disclosed herein. Act 3-1 comprises thewireless terminal 30 receiving, through its transceiver 34, a messagefrom the radio access network that indicates that measurements are to beperformed by the wireless terminal on downlink signals transmitted byone or more nodes of the radio access network or by the radio accessnetwork on uplink signals transmitted by the wireless terminal. By“downlink signals transmitted by one or more nodes of the radio accessnetwork” specifically includes but is not limited to downlink signalstransmitted by the base station, e.g. the eNodeB.

The method further comprises, as a result of or after receiving themessage, the act (act 3-2) of changing an operation mode of the wirelessterminal 30, i.e., changing operation of the wireless terminal from adiscontinuous mode to a modified mode to facilitate performance of themeasurements.

FIG. 4 illustrates a preferred version of the method of FIG. 3 whichfurther includes as act 3-3 the wireless terminal 30 reverting back fromthe modified mode to the discontinuous mode upon completion of theperformance of the measurements. In an example embodiment the revertingact 3-3 can be accomplished by radio resource control (RRC) unit 42 uponreceipt of an indication from measurement unit 44 that the measurementsof the measurement period have been completed. FIG. 4 also shows thatact 3-3 can be followed by another execution of act 3-1, and that actsof FIG. 4 can be executed essentially in looped or repetitive manner asneeded.

In several example embodiments described herein the message receivedfrom the radio access network as act 2-1 is a measurement requestmessage (MRM) which is configured to direct wireless terminal 30 toperform measurements relative to signals received by the wirelessterminal from one or more cells of the radio access network (see FIG.2). In other embodiments, such as those depicted by FIG. 13 and FIG. 14,the message received as act 2-1 indicates that the radio access networkwill perform the measurements.

As previously mentioned, a “discontinuous mode” comprises or encompassesat least one of non-reception periods between reception periods andnon-transmission periods between transmission periods. For example, adiscontinuous mode comprising non-reception periods between receptionperiods is also known as a discontinuous reception (DRX); adiscontinuous mode comprising non-transmission periods betweentransmission periods is also known as a discontinuous transmission(DTX).

Changing from a discontinuous mode to a modified mode” can compriseseveral scenarios. A first generic scenario is illustrated in FIG. 5,which generally shows the mode of the wireless terminal changing from adiscontinuous mode to a modified mode, with the modified mode comprisingeither a continuous mode or a modified discontinuous mode. More specificexamples of the generic scenario of FIG. 5 are provided in FIG. 5Athrough FIG. 5C.

FIG. 5A illustrates a situation in which the discontinuous mode is thediscontinuous reception (DRX) mode, and wherein upon receipt of themessage of act 2-1 from the radio access network the wireless terminalchanges operation to either a continuous reception mode or to a modifieddiscontinuous reception (DRX′) mode. In the FIG. 5A situation receipt ofthe message (MRM) does not alter the transmission operation mode of thewireless terminal.

FIG. 5B illustrates a situation in which the discontinuous mode is thediscontinuous transmission (DTX) mode, and wherein upon receipt of themessage of act 2-1 the wireless terminal changes operation to either acontinuous transmission mode or to a modified discontinuous transmission(DTX′) mode. In the FIG. 5B situation receipt of the message of act 2-1does not alter the reception operation mode of the wireless terminal.

FIG. 5C illustrates a situation in which the discontinuous mode includesboth the discontinuous reception (DRX) mode and the discontinuoustransmission (DTX) mode. Upon receipt of the message of act 2-1 thewireless terminal changes operation of either to a continuous mode(which includes both continuous reception and continuous transmission)or to a modified mode (which includes both modified discontinuousreception (DRX′) and modified discontinuous transmission (DTX′).

Thus, as used herein, the expression “changing from a discontinuous mode. . . to a modified mode” comprises one or more of: (1) changing mode ofthe wireless terminal (e.g., changing from a discontinuous mode [such asdiscontinuous reception (DRX) or discontinuous transmission (DTX)] to acontinuous transmission mode); (2) changing from the discontinuous mode(a first discontinuous mode) to a modified discontinuous mode (a seconddiscontinuous mode).

The changing from the (first) discontinuous mode to a modified (second)discontinuous mode can involve changing a parameter or value associatedwith the discontinuous mode, e.g., changing (e.g., shortening ordiminishing) a parameter or value such as a discontinuous reception(DRX) cycle value or a discontinuous transmission (DTX) level value.

In view of the ability of the wireless terminal 30 to revert back to thediscontinuous mode as indicated by act 3-3, the arrows of FIG. 5 andFIG. 5A-FIG. 5C are shown to be double headed. It will also beunderstood that the broken line referenced as “mode change” in any ofFIG. 5 and FIG. 5A-FIG. 5C can encompass either a mode change promptedby receipt of the message of act 2-1 or a reverting mode change which ispermitted upon completion of the measurements, e.g., upon end of themeasurement period.

FIG. 6 shows an example embodiment of wireless terminal 30 wherein radioresource control (RRC) unit 42 comprises mode controller 60. The modecontroller 60 includes mode status changer 62 which implements modechanges, such as one or more of the mode changes shown in FIG. 5 or FIG.5A-FIG. 5C, and keeps track of the current mode of operation of wirelessterminal 30.

As mentioned above, the mode change, i.e., “changing from adiscontinuous mode . . . to a modified mode” can comprise changing fromthe discontinuous mode (a first discontinuous mode) to a modifieddiscontinuous mode (a second discontinuous mode). An example way toimplement a change from a first discontinuous mode to a seconddiscontinuous mode includes changing a parameter or value associatedwith the discontinuous mode. For example, a parameter having a firstvalue in the discontinuous mode can be changed to a second value in themodified discontinuous mode. To this end, the mode controller 60 ofwireless terminal 30 of FIG. 6 is shown as comprising a register ormemory location for storing a discontinuous mode parameter value (1^(ST)parameter value register 64) and register or memory location for storinga modified mode parameter value (2^(nd) parameter value register 66).

From the foregoing it is understood that as a result of receiving themessage of act 2-1, in an example embodiment the operation of thewireless terminal can be changed from a first discontinuous mode(characterized by a first discontinuous mode parameter value [which canbe stored in 1^(ST) parameter value register 64]) to a seconddiscontinuous mode (characterized by a second discontinuous mode value[which can be stored in 2^(nd) parameter value register 66]). The seconddiscontinuous mode value is shorter (e.g., of less magnitude) than thefirst discontinuous mode parameter value.

As one example of the foregoing, in example implementations in which thediscontinuous mode is a discontinuous reception (DRX) mode, the firstdiscontinuous mode parameter value and the second discontinuous modeparameter value are differing discontinuous reception (DRX) cyclelengths. The second discontinuous mode parameter value, e.g. the DRXcycle length of the modified (second) discontinuous mode, has a smallermagnitude than the first discontinuous mode parameter value, e.g., theDRX cycle length of the first discontinuous mode.

As another example of the foregoing, in example implementations in whichthe discontinuous mode is a discontinuous transmission (DTX) mode, thefirst discontinuous mode parameter value and the second discontinuousmode parameter value are differing discontinuous transmission (DTX)levels. The second discontinuous mode parameter value, e.g. the DTXlevel of the modified (second) discontinuous mode, has a smallermagnitude than the first discontinuous mode parameter value, e.g., theDTX level of the first discontinuous mode.

FIG. 7 and FIG. 8 illustrate an example embodiment of wireless terminal30 wherein the radio resource control (RRC) unit 42 is configured tochange from the discontinuous mode in accordance with a mode changetiming factor (MCTF) which influences when a mode change occurs from thediscontinuous mode to the modified mode. FIG. 8 superimposes a timevector on the illustration of the mode change from the discontinuousmode to the modified mode, and shows a relative time positioning ofreceipt of the message of act 2-1 and the subsequent mode change.Whereas in the previous embodiments the mode change occurs as soon aspracticable after receipt of the message of act 2-1, in the FIG. 7 andFIG. 8 embodiment the mode change timing factor (MCTF) essentiallyserves to delay the mode change past the point of practicableimplementation. In some cases the mode change timing factor (MCTF) canbe an offset value (e.g., either a time duration or frame) which isrequired to occur after receipt of the message of act 2-1 before themode change is to be implemented. In other cases, rather than being arelative offset value, the mode change timing factor (MCTF) can be anindication of a particular (e.g., absolute) frame number of point intime at which the mode change is to occur (the mode change timing factor(MCTF), in such cases pointing to a mode change event which is to occurafter receipt of the message of act 2-1.

FIG. 7 serves to illustrate two separate implementations, including afirst implementation wherein the mode change timing factor (MCTF) ispre-configured at the wireless terminal prior to reception of themessage of act 2-1. To this end FIG. 7 shows radio resource control(RRC) unit 42 and its mode controller 60 as comprising mode changetiming factor (MCTF) register or memory location 68 wherein thepre-configured mode change timing factor (MCTF) can be stored. Asmentioned, the pre-configuring can occur at any point prior to receiptof the message of act 2-1, e.g., at beginning of a session, throughpre-session periodic update or administrative messages from the network,or upon initiation or power up of the wireless terminal 30.

FIG. 7 also shows another example implementation wherein a value for themode change timing factor (MCTF) is included in the message of act 2-1.This FIG. 7 alternate implementation shows the node radio resourcecontrol (RRC) unit 52 of network node 28 as including a messageformatter 70. The message formatter 70 of FIG. 7 is configured toinclude the mode change timing factor (MCTF) in the message of act 2-1.In an example implementation, the message of act 2-1 can take the formof (or be included in) any suitable RRC signaling message. The modechange timing factor (MCTF) can be inserted in any unallocated field orany newly designated field of the measurement request message (MRM),such as a measurement configuration information element, for example.

FIG. 9 and FIG. 10 illustrate an example embodiment of wireless terminal30 wherein the radio resource control (RRC) unit 42 is configured, uponcompletion of the performance of the measurements, to revert back to thediscontinuous mode from the modified mode in accordance with apost-measurement mode revert timing factor (MRTF) which influencestiming of a reversion from the modified mode to the discontinuous mode.FIG. 10 superimposes a time vector on the illustration of the modechange from the discontinuous mode to the modified mode, and shows arelative time positioning of completion of the performance of themeasurements and the subsequent mode reversion back to the discontinuousmode. Whereas in the previous embodiments the mode reversion occurs assoon as practicable upon completion of the performance of themeasurements, in the FIG. 9 and FIG. 10 embodiment the mode reverttiming factor (MRTF) essentially serves to delay the mode reversion pastthe point of practicable implementation. In some cases the mode reverttiming factor (MRTF) can be an offset value (e.g., either a timeduration or frame) which is required to occur after completion of theperformance of the measurements before the mode reversion is to beimplemented. In other cases, rather than being a relative offset value,the mode revert timing factor (MRTF) can be an indication of aparticular (e.g., absolute) frame number of point in time at which themode reversion is to occur (the mode revert timing factor (MRTF) in suchcases pointing to a mode reversion event which is to occur aftercompletion of the performance of the measurements.

FIG. 9 actually serves to illustrate two separate implementations,including a first implementation wherein the mode revert timing factor(MRTF) is pre-configured at the wireless terminal, e.g., pre-configuredprior to reception of the message of act 2-1. To this end FIG. 9 showsradio resource control (RRC) unit 42 and its mode controller 60 ascomprising mode revert timing factor (MRTF) register or memory location72 wherein the pre-configured mode change timing factor (MCTF) can bestored. As mentioned, the pre-configuring can occur at any point priorto receipt of the message of act 2-1, e.g., at beginning of a session,through pre-session periodic update or administrative messages from thenetwork, or upon initiation or power up of the wireless terminal 30.

FIG. 9 also shows another example implementation wherein a value for themode revert timing factor (MRTF) is included in the message of act 2-1.This FIG. 9 alternate implementation shows the node radio resourcecontrol (RRC) unit 52 of network node 28 as including the previouslymentioned message formatter 70. The message formatter 70 of FIG. 9 isconfigured to include the mode revert timing factor (MRTF) in themessage of act 2-1. In an example implementation, the message can takethe form of a (or be included in) any suitable RRC signaling message.The mode revert timing factor (MRTF) can be inserted in any unallocatedfield or any newly designated field of the measurement request message(MRM), such as a measurement configuration information element, forexample.

FIG. 7 and FIG. 9 thus illustrate embodiments of network nodes whereinradio resource control (RRC) unit 52 is configured to prepare a messagefor transmission to wireless terminal 30, and to include therein aparameter which specifies or influences timing of a mode change. Themode change is between a discontinuous mode and a modified mode, e.g.,in the case of FIG. 7 a mode change from a discontinuous mode to amodified mode and in the case of FIG. 9 a mode change from a modifiedmode to the discontinuous mode. In particular, the node radio resourcecontrol (RRC) unit 52 comprises message formatter 70 which is configuredto include one or both of the mode change timing factor (MCTF) and themode revert timing factor (MRTF) in the message of act 2-1. As mentionedpreviously, the discontinuous mode is configured to comprise at leastone of non-reception periods between reception periods andnon-transmission periods between transmission periods. Relative to thediscontinuous mode the modified mode is configured to shorten oreliminate at least one of following: (i) the non-reception periods, and(ii) the non-transmission periods. The transceiver is configured totransmit the message of act 2-1 to the wireless terminal over the radiointerface.

In an example embodiment the radio resource control (RRC) unit isconfigured to change from the discontinuous mode to the modified mode bydisabling one or both of discontinuous reception (DRX) and discontinuoustransmission (DTX).

In an example embodiment the measurement unit 44 of the wirelessterminal 30 is configured to perform, e.g., measurements for determiningposition of the wireless terminal. There are diverse ways in which suchmeasurements can be performed and evaluated. In one exampleimplementation the message of act 2-1 is a measurement request messagewhich is configured to direct the measurement unit 44 to measure timedifference of arrival of the signals received by the wireless terminalfrom plural cells of the radio access network. In another exampleimplementation the measurement request message is configured to directthe measurement unit 44 to measure reference signal time difference(RSTD) of signals received by the wireless terminal from plural cells ofthe radio access network.

It has been mentioned above that the message of act 2-1 can, in exampleembodiments, indicate that measurements are to be performed to determineposition of the wireless terminal. The technology disclosed hereinencompasses essentially any and all practicable ways of making suchmeasurements and the various differing types of signals that facilitatethe determination of position of the wireless terminal. Somenon-limiting examples of positioning methods are mentioned below forsake of illustration.

One technique for determination of position of a wireless terminalcomprises a determination of round trip time (RTT). The round trip time(RTT) is the time difference between the beginning of signaltransmission in the downlink and estimated first path of thecorresponding signal received in the uplink. The round trip time ismeasured at the base station. According to an example embodimentdescribed subsequently with reference to FIG. 13 and FIG. 14, if thewireless terminal (UE) is in the discontinuous transmission (DTX) modewhen the base station performs a determination of round trip time (RTT),the wireless terminal (UE) should disregard the discontinuoustransmission (DTX) and instead should continuously transmit on theuplink in response to any received downlink signal from the basestation, thereby speeding up the round trip time (RTT) measurement. Itis a user specific measurement; this means it is measured separately foreach UE in a cell. In the UTRAN system RTT is specified as a UTRANmeasurement.

Another technique for determination of position of a wireless terminalcomprises a determination of wireless terminal (UE) receive-transmittime difference (e.g., UE Rx-Tx time difference). In UTRAN FDD (WCDMA)there are two UE Rx-Tx time difference measurements: Type 1 and Type 2,which are primarily defined for call set up and positioningrespectively. See, e.g., 3GPP TS 25.215, “Physical layer; Measurements(FDD”. Of these, the first one (Type 1) is mandatory, but has worseaccuracy (±1.5 chip accuracy) than the second one (±1 chip accuracy),which is an optional measurement.

Another technique for determination of position of a wireless terminalcomprises a determination of the observed time difference of arrival(OTDOA) of signals from three cells. In WCDMA the SFN-SFN type 2measurements (See, e.g., 3GPP TS 25.215, “Physical layer; Measurements(FDD)”, which is measured by the UE on CPICH signals received from twodifferent cells, is used for determining UE positioning using thismethod. In E-UTRAN a similar measurement is done on a known pilot orreference signals. The reference signals can be normal cell specificreference signals or specific reference signals meant for positioning.In general such a measurement can be called as OTDOA. More specificallywe call this measurement as reference signal time difference (RSTD).

Another technique for determination of position of a wireless terminalcomprises normal neighbor cell measurements such as the received signalstrength, received signal quality, and path loss. These typesmeasurements can be used the pattern matching method, which is morecommonly known as the fingerprinting method. The well known examples ofsuch measurements are CPICH RSCP and CPICH Ec/No in UTRAN FDD [see,e.g., 3GPP TS 25.215, “Physical layer; Measurements (FDD”], P-CCPCH RSCPin UTRAN TDD [see, e.g., 3GPP TS 25.225, “Physical layer; Measurements(TDD)”] and RSRP and RSRQ in E-UTRAN [see, e.g., 3GPP TS 36.214,“Evolved Universal Terrestrial Radio Access (E UTRA); Physical layermeasurements”]. However, signal strength type measurements such as pathloss, CPICH RSCP, P-CCPCH RSCP and RSRP are most relevant for patternmatching positioning methods.

Thus, the technology disclosed herein encompasses definition of a set ofrules which govern behavior of the wireless terminal (UE) in DRX/DTXmodes when it is requested by the network to perform one or more of thepositioning measurements e.g. observed time difference of arrival ofsignals from two cells, reference signal time difference (RSTD), SFN-SFNtype 2 measurement in UTRAN or any other measurement used forpositioning. The technology disclosed herein encompasses, as eitherseparate or combinable features, e.g., methods and apparatus forperforming positioning measurements in discontinuous reception (DRX) aswell as methods and apparatus for performing positioning measurements indiscontinuous transmission (DTX).

In some embodiments encompassed hereby the network requests the wirelessterminal (UE) to perform positioning measurements such as timedifference of arrival of signals from two cells for two or more set ofcells. These sets of cells should preferably be located in differentbase station sites. It is assumed that the wireless terminal (UE) is ina discontinuous mode (e.g., a DRX state) when such a request is receivedfrom the network. There are several facets of this part of thetechnology disclosed herein:

According to the first facet, upon receiving a request for measurement,the UE disregards the DRX cycle and goes into the continuous receptionmode. The UE stays in the continuous reception mode until it hasperformed all the requested positioning measurements. After thecompletion of all the required measurements the wireless terminal (UE)returns or reverts to the discontinuous reception (DRX) state. Such arule can be pre-defined in the standard so that the network is aware ofthe wireless terminal (UE) behavior in the discontinuous reception (DRX)mode.

According to a second facet, upon receiving the request for measurementthe wireless terminal (UE) does not fully disregard the DRX cycle.Rather, the wireless terminal (UE) shortens its DRX cycle. The wirelessterminal (UE) operates using shorter DRX cycle until it has performedall the requested positioning measurements. After the completion of allthe required measurements the UE returns or reverts to the initial DRX,which was used prior to the reception of the measurement requests. Sucha rule can also be pre-defined in the standard to make the network awareof the UE behavior in the DRX mode. The shorter DRX cycle can bepre-configured in the wireless terminal (UE) initially. Alternatively,it can also be a pre-defined DRX cycle such as the shortest possible DRXcycle or certain specific DRX cycle, e.g. 40 ms of periodicity.Alternatively the shorter DRX can be signaled in the same measurementcontrol message, which contains request for performing the positioningmeasurements. In prior art systems (in E-UTRAN) the wireless terminal(UE) can be pre-configured with two DRX cycles e.g. one short and onelong. This second facet is useful in case the wireless terminal (UE) iscapable of meeting the required measurement accuracy with a shorter DRXcycle. In this way wireless terminal (UE) can still save its batterypower to some extent.

As an example of the foregoing, assume the wireless terminal (UE) isusing DRX cycle=1.28 seconds. Upon receipt of the positioningmeasurement request from the network node the wireless terminal (UE)starts operating using the DRX cycle=40 ms until it has completed allthe measurements. After completion of the measurement, the UE returns toDRX cycle=1.28 seconds.

According to a third facet the time instance or any relative time offsetwhen the UE goes into continuous mode or when it shortens its DRX cycleto perform positioning measurements can also be pre-defined. See themode change timing factor (MCTF) mentioned above. Alternatively suchparameter can be signaled to the wireless terminal (UE) along with themeasurement request or it can be pre-configured initially at thewireless terminal (UE), e.g. at the start of the session.

Similarly according to a fourth facet the time instance or any relativetime offset when the UE shall return or revert to the initial DRX cycleafter perform positioning measurements can also be pre-defined. See themode revert timing factor (MRTF) mentioned above. Alternatively it canalso be signaled to the wireless terminal (UE) as a parameter along withthe measurement request or it can be pre-configured with initially atthe wireless terminal (UE) e.g. at the start of the session.

Overall the above facets correspond to the fact that the positioningmeasurements are of higher priority than the discontinuous mode, e.g.,than the DRX. Thus according to a fifth facet, it can simply bespecified by standard or otherwise that the positioning measurements areof higher priority than the DRX or that the wireless terminal (UE) is tooverride the DRX operation or ignore the DRX operation or shorten theDRX when performing the positioning measurements (e.g., when performingtime difference of arrivals of signals from two cells). In this way thedetails of the methods in DRX shall be left for wireless terminal (UE)implementation without explicit standardization. Yet according toanother embodiment it can also be specified that wireless terminal (UE)when in a discontinuous mode and requested to perform positioningmeasurements shall fulfill the measurement requirements corresponding tonon-DRX case (continuous reception case) or those corresponding toshorter DRX. This means the measurement period and other requirementsare the same as for the non DRX case or for the short DRX case.

As mentioned above, the wireless terminal (UE) can either disable thediscontinuous mode (e.g., DRX) or it can shorten the DRX cycle upon thereception of the positioning measurement request. Some example,non-limiting, scenarios of the technology disclosed herein areillustrated in FIG. 11 and FIG. 12

The scenario of FIG. 11 encompasses an example case wherein the DRXcycle is completely disabled by the UE (e.g., the first facet) uponreceiving the request for performing the positioning measurement: e.g.,RSTD. As shown in FIG. 11 initially the wireless terminal (UE) is in aDRX state (act 11-1). The wireless terminal (UE) then receives a RSTDmeasurement request (act 11-2) from the network. The request messagefrom the network may also include the time instances (e.g. sub-frame ortime offset, such as the mode change timing factor (MCTF) mentionedabove) when the wireless terminal (UE) is to disable its DRX and when toenable the DRX after performing the measurement. Otherwise the wirelessterminal (UE) determines the time instances or time offsets from thepre-defined values or rules. The wireless terminal (UE) then disablesthe DRX cycle (act 11-3) and starts performing RSTD measurement (act11-4) from multiple set of paired cells e.g. N (N>1) set; serving celland N neighbor cells. The wireless terminal (UE) is capable ofperforming all the requested RSTD measurements within the specifiedduration, e.g., according to the performance requirements. The durationover which the wireless terminal (UE) remains in non DRX (continuousreception mode) is therefore on the order of the RSTD measurement periodfor non DRX case. Therefore, when the measurement timer expires (11-5)the wireless terminal (UE) enables the DRX mode (act 11-6), e.g.,reverts back to the discontinuous mode.

FIG. 12 illustrates an example, non-limiting specific scenario whereinthe DRX cycle is shortened by the wireless terminal (UE) upon receivingthe request for performing the positioning measurement, e.g., RSTD. Asshown in FIG. 15, initially the wireless terminal (UE) is in a DRX state(act 12-1). The wireless terminal (UE) receives the RSTD measurementrequest (act 12-2) from the network. The request message from thenetwork may also include the time instances (e.g. sub-frame or timeoffset) when the wireless terminal (UE) is to shorten its DRX cycle andwhen to return to the initial DRX state after performing themeasurement. Otherwise the wireless terminal (UE) determines the timeinstances or time offsets from the pre-defined values or rules. Thewireless terminal (UE) then shortens its DRX cycle (act 12-3) and startsperforming RSTD measurement (act 12-4) from multiple set of paired cellse.g. N (N>1) set; serving cell and N neighbor cells. The duration overwhich the wireless terminal (UE) stays in the shorter DRX cycle is onthe order of the RSTD measurement period corresponding to the shorterDRX cycle. Therefore when measurement timer expires (act 12-5) thewireless terminal (UE) returns to the initial DRX state (act 12-6).

Although the examples of FIG. 11 and FIG. 12 feature RSTD, a personskilled in the art can realize that the FIG. 11 and FIG. 12 examples caneasily be applied to other positioning measurements such as UTRANSFN-SFN type 2, observed time difference of arrival (OTDOA) of signalsfrom two cells or any other positioning measurement including such as,path loss, signal strength and signal quality.

The discontinuous transmission (DTX) can occur due to any type of idlegaps. The gaps are generally used for performing measurements oninter-frequency carriers and/or inter-RAT carriers (i.e. on technologiesother than the one corresponding to the serving carrier). In UTRAN andE-UTRAN the periodical compressed mode patterns and idle gapsrespectively are used for performing these types of measurements.

The DTX is also used in UTRAN for other purposes such as to reducetransmission power, received interference, noise rise etc. For instance,in WCDMA, where traditionally continuous power control and hence acontinuous DPCCH is used, the discontinuous uplink power control feature(i.e. by configuring a discontinuous dedicated physical control channel(DPCCH)), which is configurable by the network, allows the network toreduce uplink noise rise and UE transmission power. The exact DTXpattern e.g. periodicity and duration of the DTX/idle occasion/gap areset by the network according to the desired scenario.

According to a sixth facet of the technology disclosed herein therequest for the positioning measurement (e.g. RSTD or SFN-SFN type 2etc), the wireless terminal (UE) disables the DTX and goes intocontinuous transmission mode. After performing the positioningmeasurement the wireless terminal (UE) returns to the DTX mode. As incase of DRX the time instances or time offsets at which the DTX isdisabled and enabled can be signaled by the network or can be derivedfrom the pre-defined rule or can be pre-defined values.

According to a seventh facet of the technology disclosed herein uponreceiving the request for the positioning measurement (e.g. RSTD orSFN-SFN type 2 etc), the wireless terminal (UE) does not completelydisable the DTX, but rather reduces the DTX cycle or the level of theDTX, e.g. the UE may go from DTX periodicity of 640 ms to 80 ms. The DTXcycle may also be pre-defined that upon the request. The wirelessterminal (UE) goes to the shortest possible DTX level or alternativelythe wireless terminal (UE) operates according to the pre-configured orpre-defined DTX/idle gap. After performing the positioning measurementthe wireless terminal (UE) returns to the normal or to the initial DTXmode. As in case of DRX, the time instances or time offsets at which thewireless terminal (UE) transmits with shorter DTX and resumes withnormal DRX can be signaled by the network or can be derived from thepre-defined rule or can be pre-defined values.

A longer DTX cycle or idle gaps (such as compressed mode gaps ormeasurement gaps) may particularly lead to longer measurement periodsand response times of the positioning measurements done at the basestation (e.g. round trip time or one way propagation delay). This isbecause due to the DTX or idle gaps the radio network node will sparselyreceive the wireless terminal (UE) transmitted signals. This problem issolved, e.g., by the eighth facet of the technology disclosed herein.

FIG. 13 shows a representative network node 28 and a representativewireless terminal 30 suitable for implementation the eighth facet of thetechnology disclosed herein wherein the network node 28 directs thewireless terminal 30 to discontinue the discontinuous transmission (DTX)mode while the network node makes position measurements for the wirelessterminal. For this eighth facet the network node 28 of FIG. 13 includesnode measurement unit 80.

According to this eighth facet (illustrated in FIG. 13 and FIG. 14) thewireless terminal (UE) disables the DTX cycle to facilitate the uplinkpositioning measurement, e.g. round trip time or one way propagationdelay etc. In this way the radio network node such as a base station,Node B or eNode B shall frequently receive the wireless terminal(UE)-transmitted signal and will be able to promptly perform thepositioning related measurement and determined the UE position in ashorter duration. FIG. 14 shows example, non-limiting acts or steps forthe eighth facet, and particularly shows as act 14-1 the network nodesignaling the wireless terminal (UE) a message or a command indicatingthe UE to disable the DTX over specified (e.g., certain) time period(T1). As act 14-2 the wireless terminal (UE) discontinues thediscontinuous transmission (DTX) mode. During the certain or specifiedtime period T1 the network node performs the positioning measurements(act 14-3). After the time period T1, the UE resumes the DTX operation(act 14-4).

In the eighth facet illustrated by FIG. 13 and FIG. 14 the time periodT1 can be either specified by the network node in a message to thewireless terminal or a pre-defined value, e.g., the measurement periodof the measurement quantity in the non DTX case. In that case thenetwork signaled message shall simply indicate to the wireless terminal(UE) that the network shall perform the positioning measurement.Therefore UE shall ignore the DTX until a pre-defined time.

Thus, in the eighth facet the network indicates to the wireless terminal(UE) that the network is now performing measurement. So either networkindicates UE to disregard DTX over certain time. Another way is thatnetwork simply sends pre-defined message or signal to UE. Thepre-defined message implies according to pre-defined rule that UE is todisregard DTX over certain pre-defined time period.

It has been mentioned several times above that a longer DRX cycle or alonger DTX cycle or idle gaps (such as compressed mode gaps ormeasurement gaps) may lead to longer measurement periods and thus delaythe determination of the position of the wireless terminal (UE). FIG. 15illustrates a situation in which the wireless terminal has beenoperating in a discontinuous mode (either one or both of DRX or DTX)having a cycle length of 2.56 second, with four samples of each of fourcells. In the FIG. 15 discontinuous mode situation the measurementperiod of reference signal received power (RSRP), which is LTEmeasurement quantity, is approximately 10.28 seconds. FIG. 15 also showsthe shortening of the measurement period that occurs upon a mode changeto a modified mode such as a non-discontinuous mode, and particularly tothe example situation of FIG. 16. Accordingly, FIG. 15 shows that, inview of the mode change, the measurement period has been reduced from10.28 seconds to 200 milliseconds. The significantly shortenedmeasurement period enables a more prompt and accurate determination ofthe position of the wireless terminal (UE).

The continuous transmission helps speed up measurements but alsoincreases interference. Therefore a suitable value of DTX cycle or levelof DTX would lead to reasonable measurement period of the positioningmeasurement and acceptable response time of the determined position ofthe wireless terminal (UE). This objective is achieved by the ninthfacet of the technology disclosed herein. Thus according to this ninthfacet the wireless terminal (UE) uses shorter DTX cycle/idle gaps tofacilitate the radio network node performing the positioning measurementover a shorter period of time. As in the previous case, the network hasto signal the UE when to shorten the DTX/idle gaps and over certainduration (T2). Either a shorter DTX cycle can be signaled to the UE oralternatively a pre-defined rule may also be specified. For instance thepre-define rule could require the UE to operate according to a shorterpre-configured or pre-defined DTX/idle gap; another possibility is thatthe wireless terminal (UE) uses the shortest possible DTX level. Theduration (T2) can also be a pre-define value rather than a signaledvalue.

According to a tenth facet of the technology disclosed herein it cansimply be specified or prescribed (e.g., standardized) that thepositioning measurements are of higher priority than the DTX/idlegaps/measurement gaps/compressed mode gaps, otherwise specified that theUE is to override or ignore or shorten the DTX/idle gaps/measurementgaps/compressed mode gaps when the positioning measurements areperformed either by the wireless terminal (UE) or by the network orboth. In this way the details of the methods in DRX or idle gaps shallbe left for wireless terminal (UE) implementation without explicitstandardization. Yet according to another embodiment it can also bespecified that when the wireless terminal (UE) is in DTX and positioningmeasurements are performed either by wireless terminal (UE) or by theradio network node the measurement requirements corresponding to non DTXcase (continuous transmission case) or those corresponding to shorterDTX shall be met. This means the measurement period and otherrequirements are the same as for the non DTX case or for short DTX case.

In practice both DTX and DRX modes may be used. For instance when thewireless terminal (UE) is configured in DRX, the measurement gaps forperforming the neighbor cell measurements may also be activated inparallel.

Hence according to an eleventh facet of the technology disclosed hereinthe wireless terminal (UE) disables both DRX and DTX (or any types ofidle gaps) when the positioning related measurements (i.e. disables theDRX/DTX over the duration of measurements) are carried out either by thewireless terminal (UE) or by the radio network node such as a basestation or by both wireless terminal (UE) and the radio network node.

According to a twelfth facet of the technology disclosed herein the UEuses both shorter DRX and shorter DTX when the positioning relatedmeasurements (i.e. uses shorter DRX/DTX over the duration ofmeasurements) are carried out either by the UE or by the radio networknode such as a base station or by both UE and the radio network node.

According to a thirteenth facet of the technology disclosed herein anycombination of the methods related to the positioning measurements inDRX and DTX disclosed herein can be used.

All the preceding embodiments encompass and/or comprise the rules,methods, and procedures pertaining to the measurements related to theterrestrial positioning methods (e.g. UE based and network based UTDOAetc) in DRX.

In case of GNSS or A-GNSS the wireless terminal (UE) is required tofully or partially perform measurements on signals received from certainnumber of satellites, e.g. number of visible satellites, identity ofsatellites, etc. If the wireless terminal (UE) is in DRX mode themeasurements shall be delayed. This in turn will lead to longer responsetime in the determination of the wireless terminal (UE) position.

According to the fourteenth facet of the technology disclosed herein allthe methods described herein can also be used for performing satellitebased positioning measurements, e.g. A-GPS measurements. This means thewireless terminal (UE) can either ignore DRX/DTX or can shorten theDRX/DTX when performing GNSS or A-GNSS or A-GPS related measurements.

The technology disclosed herein thus encompasses, among other things,the following, alternatively or collectively:

In the discontinuous reception (DRX) state the wireless terminalperforms a reference signal time difference (RSTD) measurement over themeasurement period corresponding to the non-discontinuous reception(DRX).

Regardless of whether the wireless terminal is in the discontinuousreception (DRX) mode/state or not, the wireless terminal performs thereference signal time difference (RSTD) measurement over the samemeasurement period.

If the wireless terminal is configured in the discontinuous reception(DRX) mode/state, then upon receiving the reference signal timedifference (RSTD) measurement from the network, the wireless terminalignores the discontinuous reception (DRX) cycle during the measurementperiod of the reference signal time difference (RSTD) measurement.

If the wireless terminal is configured in the discontinuous reception(DRX) mode/state, then upon receiving the reference signal timedifference (RSTD) measurement request from the network the wirelessterminal goes into a non-DRX state (or shortens its DRX cycle) duringthe measurement period of the reference signal time difference (RSTD).

According to the fifteenth facet of the technology disclosed herein thewireless terminal (UE) disregards DRX and/or DTX when there is criticalsituation such as emergency situation or public warning. The emergencyor public warning may be caused due to one or several reasons such as:hurricane, typhoon, tornado, flood, acts of terrorism, fire etc. In oneembodiment when UE is operating under DRX and/or DTX, then uponreceiving any emergency related information from the network node, theUE disregards the DRX and/or DTX over certain time period (Te). Theperiod Te can be a pre-defined period or it can be a value signaled bythe network. The emergency information including Te can be sent to theUE via broadcast channel or via UE specific channel or via any suitablechannel. The UE can either be explicitly indicated by the network via asignaling message to disregard the DRX and/or DTX states. Alternativelythe disabling of the DRX and/or DTX states under emergency can also bebased on a pre-defined rule. For instance a pre-defined rule can bespecified according to which when UE initiates an emergency call orsends any request related to warning or emergency, then the UE disablesthe DRX and/or DTX over a pre-defined time or until the completion ofthe emergency call. After the public warning or emergency is over the UEreverts to the normal DRX and/or DTX operation. The disabling of DRXand/or DTX in emergency situation enables the UE and network toestablish faster communication and also allows the UE and/or networknode to perform faster measurements required for various reasons e.g.for determination of UE position, for better mobility performance etc.

According to sixteenth facet of the technology disclosed herein when UEis operating in DRX and/or DTX and if there is critical situation suchas emergency or public warning, the UE does not completely disable theDRX and/or DTX states rather it shortens its DRX and/or DTX cycles overa time period (Ts); Ts can be a pre-defined value or a value signaled bythe network node to the UE. The shorter values of DRX/DTX cycles can bepre-defined for use during the emergency situation or they can besignaled to the UE in emergency message via broadcast channel or via UEspecific channel or via any suitable channel. After public warning oremergency is over the UE reverts to the normal DRX and/or DTX operation.The shortening of DRX and/or DTX in emergency situation has severaladvantages. It enables the UE and network to establish fastercommunication and allows the UE and/or network node to performrelatively faster measurements required for various reasons e.g. fordetermination of UE position, for better UE mobility performance etc.Another advantage is that UE can still save its battery power which isimportant in such emergency situation.

FIG. 17 and FIG. 18 illustrate the fifteenth and sixteenth facets of thetechnology disclosed herein. FIG. 17 shows example representative actsor steps involved in a method according to the fifteenth and sixteenthfacets of the technology disclosed herein. Act 17-1 comprisesrecognizing that an emergency situation exists (the recognition being inaccordance with any of the foregoing examples). The methods furthercomprise, as a result of or after the recognition, the act (act 17-2) ofchanging an operation mode of the wireless terminal 30, i.e., changingoperation of the wireless terminal from a discontinuous mode to amodified mode to facilitate performance of the measurements. FIG. 18illustrates a preferred version of the method of FIG. 17 which furtherincludes as act 17-3 the wireless terminal 30 reverting back from themodified mode to the discontinuous mode. Such reverting can occur uponany of the example criteria described herein, e.g., upon expiration of apredetermine time interval or indication/realization that the emergencysituation has terminated. In an example embodiment the changingoperation of act 17-3 and/or the reverting act 17-3 can be accomplishedby radio resource control (RRC) unit 42. Aspects of the fifteenth andsixteenth facets of the technology, including but not limited to themeaning of discontinuous mode and modified mode and applicability toeither or discontinuous reception (DRX) and discontinuous transmission(DTX), are understood with reference to other embodiments and examplesdescribed herein.

The technology disclosed herein encompasses for affords many advantages.Example, non-limiting advantages include the following:

-   -   The wireless terminal (UE) in DRX state can perform and report        the measurements to be used for determining its positioning in a        shorter duration. This, in turn, reduces the response time to        determine the wireless terminal (UE) position when the wireless        terminal (UE) is in DRX state.    -   By the virtue of the embodiment which allows the use of shorter        DRX/DTX cycle, the measurement period and response times are        reasonably reduced.    -   Reasonable interference and noise rise levels can be maintained        by using shorter and appropriate DTX/gaps.    -   Reasonable UE power saving can be achieved by using shorter and        appropriate DRX cycle.    -   The requirements of the emergence calls, which require fast        determination of the UE position, can be met when the wireless        terminal (UE) is in DRX.

Although the description above contains many specificities, these shouldnot be construed as limiting the scope of the invention but as merelyproviding illustrations of some of the presently preferred embodimentsof this invention. Thus the scope of this invention should be determinedby the appended claims and their legal equivalents. Therefore, it willbe appreciated that the scope of the present invention fully encompassesother embodiments which may become obvious to those skilled in the art,and that the scope of the present invention is accordingly to be limitedby nothing other than the appended claims, in which reference to anelement in the singular is not intended to mean “one and only one”unless explicitly so stated, but rather “one or more.” All structural,chemical, and functional equivalents to the elements of theabove-described preferred embodiment that are known to those of ordinaryskill in the art are expressly incorporated herein by reference and areintended to be encompassed by the present claims. Moreover, it is notnecessary for a device or method to address each and every problemsought to be solved by the present invention, for it to be encompassedby the present claims. Furthermore, no element, component, or methodstep in the present disclosure is intended to be dedicated to the publicregardless of whether the element, component, or method step isexplicitly recited in the claims. No claim element herein is to beconstrued under the provisions of 35 U.S.C. 112, sixth paragraph, unlessthe element is expressly recited using the phrase “means for.”

What is claimed is:
 1. A method of operating a wireless terminal incommunication with a radio access network over a radio interface, thewireless terminal being of a type capable of operating in adiscontinuous reception (DRX) mode comprising non-reception periodsbetween reception periods, the method comprising: while the wirelessterminal is in the DRX mode, receiving a message from the radio accessnetwork indicating that measurements are to be performed by the wirelessterminal on downlink signals transmitted from one or more cells of theradio access network; and in response to receiving the message,shortening or eliminating the non-reception periods of the DRX mode. 2.The method of claim 1, wherein receiving a message indicating thatmeasurements are to be performed comprises receiving a messageindicating that detection of cell identity is to be performed.
 3. Awireless terminal configured for communication with a radio accessnetwork over a radio interface, the wireless terminal comprising: atransceiver configured to receive a message from the radio accessnetwork indicating that measurements are to be performed by the wirelessterminal on downlink signals transmitted from one or more cells of theradio access network; the wireless terminal characterized by: acomputer-implemented radio resource control (RRC) unit configured to, inresponse to receiving the message, shortening or eliminatingnon-reception periods of a discontinuous reception (DRX mode.
 4. Thewireless terminal of claim 3, wherein receiving a message indicatingthat measurements are to be performed comprises receiving a messageindicating that detection of cell identity is to be performed.